The development of data analysis techniques that are appropriate for the analysis of complex sample surveys is an ongoing project. Several software packages such as SUDAAN and Westvar are available for the analysis of complex sample survey data. They use different mathematical algorithms (e.g., Taylor series vs "Jackknife" procedures) and differ in other features as well. Data from multiple large national oral health surveys are being used to analytically test and evaluate these software packages in five areas: (1) appropriate methodology for complex survey samples (2) portability (3) reliability/numerical accuracy (4) computational efficiency (5) ease of use (6) handling of very large sample sizes